Tunable cavity resonators are electronic components that are useable as filters for radio frequency electromagnetic signals, among other types of signals. In particular, tunable cavity resonators using the evanescent mode cavity-based implementation are effective filters that are low-loss and widely tunable. Additionally, cavity resonators using the evanescent mode implementation typically offer a good balance between filter size, signal loss, spurious-free dynamic range, and tuning range.
Tunable cavity resonators typically include either a piezoelectric tuning device or an electrostatic microelectromechanical systems (“MEMS”) diaphragm tuning device. Piezoelectrically-tuned cavity resonators typically yield excellent radio frequency filtering results. These types of tuning devices, however, are typically large, with a diameter of approximately twelve to thirteen millimeters, and have slow response speeds that are on the order of one millisecond or more. MEMS diaphragms also typically yield excellent radio frequency filtering results, but have a low unloaded quality factor (“Qu”) due to effects from the biasing network that is used to control the MEMS diaphragm. Accordingly, known tuning devices for cavity resonators exhibit a tradeoff between size, unloaded quality factor, frequency tuning, and tuning speed.
Accordingly, further developments based on one or more of the above-described limitations are desirable for tunable cavity resonators.